Recently, in order to reduce the cost and decrease the thickness, there are cases where a camera module, which is mounted in a cellular phone or the like, is configured by a small number of lenses or lenses having a low modulation transfer function (MTF) characteristic. As a technique for apparently reducing blurring of an image by performing digital signal processing, for example, an edge emphasis process using a band pass filter (BPF) is known.
In the edge emphasis process, a value is added to an edge portion (addition of an overshoot) or is subtracted from the edge portion (addition of an undershoot) by performing a predetermined process for an edge component that is extracted by the BPF. When an image including a dull edge portion is obtained due to the use of lenses having a low MTF characteristic, in the edge emphasis process performed based on the image, there is a problem in that blurring or a noise is generated due to expansion of an overshoot or an undershoot.
As a technique for solving such a problem, for example, there are cases where blurring correction is applied through an extended depth of field (EDOF) process. In applying the EDOF process, a special lens for the EDOF process is required, and digital processing that is appropriate for the performance of the lens needs to be performed.
The application of the EDOF process leads to a decrease in the versatility, an increase in circuit size, an increase in required memory capacity, and the like due to the necessity of a special configuration used for the EDOF process, and accordingly, there are problems from the viewpoints of the chip size and the power consumption.